With more eyeballs all bugs are seen (Linus Torvalds) > Doing a quick check on proportions and shapes of different tracks from > different portion of > the map, I think the data supplied is trash. :-(
As per Rally's assessment, I am holding-off to importing this data. Unless, others can make sense of how we can use this for OSM. I can provide a download link to anyone who wants to play around with it. If you think it's useable for OSM, we can discuss this here. Personally, nanghinayang lang ako, if this is good data (or at least useful) a good chunk of roads will be added to OSM. But as Rally said, > So, we'll surely get in trouble or lose good reputation for uploading bad > data, hehe I'd rather accept someone saying we have wrong data because of an honest newbie experimenting around than importing data we know having big problems. Thanks Rally for doing the assessment. Any other comments? On Sat, Jun 6, 2009 at 11:49 AM, Eugene Alvin Villar<sea...@gmail.com> wrote: > I was about to ask you to ask them how they compiled their data. It > obviously wasn't traced over Google Earth nor taken using GPS tracks. I > think Rally might have guessed their method correctly. > > > On Sat, Jun 6, 2009 at 11:26 AM, maning sambale <emmanuel.samb...@gmail.com> > wrote: >> >> ---------- Forwarded message ---------- >> From: Rally de Leon <rall...@gmail.com> >> Date: Fri, Jun 5, 2009 at 9:36 PM >> Subject: Re: [talk-ph] RFC: importing Palawan roads >> To: maning sambale <emmanuel.samb...@gmail.com> >> >> >> Doing a quick check on proportions and shapes of different tracks from >> different portion of the map, I think the data supplied is trash. :-( >> >> I've seen shape files very much like this (like the one I obtained >> from Taytay Assessor) that was just traced over TAX MAPPING paper >> sheets (purely based on shape guestimation and visual >> ratio-and-proportion) then converted then to autocad drawings. I've >> seen them how they draw the lot shapes on paper (during the time >> nagtatambay ako sa assessor). It's doable if you know where to chop >> the areas (eg. per subdivision or per purok), then convert it back to >> raster image, then georectify that image (for every area) which will >> need actual gps waypoints, then trace your vector lines over the >> raster layer. But what's the point? we are talking of the whole >> palawan.The purpose of this data is just for assessment and for >> assigning PIN codes on the tax declaration, not for navigation nor for >> making proportionally correct paper map. >> >> I highly doubt that the data came from actual field survey. Because >> I've traced Namria topo maps before (in Luzon datum), and they were >> proportionally correct when I translated them to WGS84. My old >> personal garmin maps were made this way with fairly high degree in >> accuracy. But in this case, the shp file have wrong proportions, >> different shapes, different angles, a lot of extraneous lines and >> streets (that doesn't make sense), really bad. I tried Luzon-Mean, >> Luzon-Philippines, Luzon-Mindanao (all failed), so I tried to cheat by >> just dragging them over google satellite image, still failed, won't >> fit. No wonder you can't make it fit using all available datum, hehe. >> nadaya yata tayo dun. If we are lucky enough to have one subdivision >> fit the roads of a satellite image (yahoo or google), the adjacent >> subdivision won't (as i've tried it since this was really easy to do >> in trackmaker pro). In my experience, even those subdivisions as far >> as 500meters from your reference tracklog should still fit the >> satellite image with your extended vector traces; in this case, even >> the neighboring streets a few blocks away doesn't. >> >> So, we'll surely get in trouble or lose good reputation for uploading >> bad data, hehe. I suggest we just recruit gps-tracker volunteers in >> any of the streets in palawan (where there are good hi-res satellite >> images), and lets do it the old fashion way. >> >> Call back the source of this data and ask him to confess (if they >> really made that survey). kung ayaw umamin, i-torture natin ;-D >> >> >> On Fri, Jun 5, 2009 at 6:17 PM, maning sambale >> <emmanuel.samb...@gmail.com> wrote: >> > >> > I tried every projection parameters I can think of pero may shift pa >> > rin, anyway the shift is systematic so moving the whole data to fit >> > existing OSM roads, should be straightforward. >> > >> > Here's the data, around 7 MB: >> > http://esambale.wikispaces.com/file/view/palawan_roads.zip >> > >> > Tirahin mo sya! >> > >> > On Fri, Jun 5, 2009 at 6:01 PM, Rally de Leon<rall...@gmail.com> wrote: >> > > can you send me a copy of this palawan tracks? how big? i'm sure you >> > > already >> > > have your methods of converting to wgs84. >> > > >> > > but let me see what i can do (para meron naman akong mapaglibangan >> > > this >> > > weekend). don't worry, i'm not going to trace over googleearth. (lets >> > > just >> > > compare notes later) :-) >> > > >> > > i'm just going to try if it's as easy as shifting the entire thing on >> > > the >> > > built-in datum-shifter of GPS trackmaker, if it works and passed our >> > > counterchecks, >> > > then the data goes to JOSM for additional validations, edits and >> > > tagging. >> > > >> > > else if it's not that easy, maybe we can use a method of shifting >> > > arbitrary >> > > control points. (most likely, palawan is on Zone 2 of Luzon Datum, >> > > then >> > > convert to WGS84) (practically, all main Luzon island is on Zone 3 - >> > > the one >> > > used by surveyors). The alignment of these "luzon-datum tracks" to the >> > > "computed WGS84 control points" can be done entirely within JOSM by >> > > just >> > > dragging the entire tracks. We have many ways to check the accuracy >> > > afterwards. medyo barok (as we will use graphical method - JOSM's is >> > > very >> > > good at this), but it may work without the need to for mathematical >> > > conversions and without the need to rely on googleearth alignments. >> > > >> > > On Fri, Jun 5, 2009 at 2:51 PM, maning sambale >> > > <emmanuel.samb...@gmail.com> >> > > wrote: >> > >> >> > >> > There is no online map we can compare the traces to to see how >> > >> > accurate >> > >> I'm doing it when I got this message. :) >> > >> >> > >> See for yourself over GEarth (blue is OSM, red is the road data). >> > >> http://farm4.static.flickr.com/3566/3596753363_51c00bb5f3_o.jpg >> > >> >> > >> Notice the shift? >> > >> >> > >> (copyright image of DigitalGlobe and Google included to abide by it's >> > >> Terms of Use) :) >> > >> >> > >> >> > >> On Fri, Jun 5, 2009 at 2:18 PM, Andre >> > >> Marcelo-Tanner<an...@enthropia.com> >> > >> wrote: >> > >> > There is no online map we can compare the traces to to see how >> > >> > accurate >> > >> > it is? >> > >> > >> > >> > _______________________________________________ >> > >> > talk-ph mailing list >> > >> > talk-ph@openstreetmap.org >> > >> > http://lists.openstreetmap.org/listinfo/talk-ph >> > >> > >> > >> >> > >> >> > >> >> > >> -- >> > >> cheers, >> > >> maning >> > >> ------------------------------------------------------ >> > >> "Freedom is still the most radical idea of all" -N.Branden >> > >> wiki: http://esambale.wikispaces.com/ >> > >> blog: http://epsg4253.wordpress.com/ >> > >> ------------------------------------------------------ >> > >> >> > >> _______________________________________________ >> > >> talk-ph mailing list >> > >> talk-ph@openstreetmap.org >> > >> http://lists.openstreetmap.org/listinfo/talk-ph >> > > >> > > >> > >> > >> > >> > -- >> > cheers, >> > maning >> > ------------------------------------------------------ >> > "Freedom is still the most radical idea of all" -N.Branden >> > wiki: http://esambale.wikispaces.com/ >> > blog: http://epsg4253.wordpress.com/ >> > ------------------------------------------------------ >> >> >> >> >> -- >> cheers, >> maning >> ------------------------------------------------------ >> "Freedom is still the most radical idea of all" -N.Branden >> wiki: http://esambale.wikispaces.com/ >> blog: http://epsg4253.wordpress.com/ >> ------------------------------------------------------ >> >> _______________________________________________ >> talk-ph mailing list >> talk-ph@openstreetmap.org >> http://lists.openstreetmap.org/listinfo/talk-ph > > > > -- > http://vaes9.codedgraphic.com > -- cheers, maning ------------------------------------------------------ "Freedom is still the most radical idea of all" -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ ------------------------------------------------------ _______________________________________________ talk-ph mailing list talk-ph@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ph
